Electrical Issue

[john.frisina]

Hi All,

Got a weird one:

At times I get a bad whine through my front left speaker. I thought it was just some electrical interference but it comes and goes. I bought a filter but am yet to install it so I don't if it will cure that problem, however, I now have another possibly related issue..

Now, whenever the whine comes back, my tacho needle starts twitching and jumping, the radio turns on and off and when the a/c compressor or cooling fans kick in the car just stops if I'm not moving. When I'm moving the radio just turns on and off with the rpm flicker..

Any ideas?

[Cory W]

It's time to clean your electrical connections and grounds. The ground point on the radio/HVAC plate requires center console removal but is worth it.

Questions:
Is the radio stock or aftermarket?
Do you notice the tach jumping when you switch on your high beams, for example?
Is your alternator original/stock or replacement? If replacement, how long has it been on the car?
What is the voltage reading in your car (I'm talking the readout of a multimeter on the battery more than the voltage gauge on the instrument panel)

Over the winter, I cleaned all the grounds on the other car up here. I also supplemented the original battery to frame ground with one to the transmission.
Just this week, I cleaned up the alternator mounts, wires and connections on that car, and it made a world of difference in vehicular voltage and how it ran.

[jawn101]

Big +1 to Cory's statement here. Check out this video I took before cleaning my grounds. I turn on the A/C and you can see the tach freak out. At about 50 seconds I flick on the high beams and it flies all the way to 4000 RPM.


http://www.youtube.com/watch?v=AmFoVVhk94M

I bet that's what you're seeing as well. I spent an afternoon cleaning the three primary ground points at the front radiator support, center console, and installed an upgraded main frame ground and that behavior is completely gone. It's a great investment of half a day and you won't regret it.

I also replaced my fuse box, all my relays, installed an upgraded alternator and low-current radiator fans... all great ideas, but the grounds are job #1.

[john.frisina]

That's it!!

My flicking is a little more erratic but that's basically it..

When I did test the voltage reading (checked earthing to the frame as well) it was all normal (15volts i think? Can't remember but mechanic gave it the ok). However, it wasn't making the speaker whine at the time. It only does it when the speaker whine is happening.

In answer to Cory's questions:

Aftermarket CD player.
No Jumping with the lights. Just happens when the radio on and fans kick in.
Not sure about the alternator.. I think it is a replacement.. Could be original or about 6 years old (thats when the last major work was done on the car..)

Are the location of the grounds in the Workshop manual?

The low voltage fans are a great idea as well jawn as they draw a lot of power..

[Cory W]

That's it!!

My flicking is a little more erratic but that's basically it..
When I did test the voltage reading (checked earthing to the frame as well) it was all normal (15volts i think? Can't remember but mechanic gave it the ok). However, it wasn't making the speaker whine at the time. It only does it when the speaker whine is happening.

Don't you love the information that people come up with to help on here?



In answer to Cory's questions:
Aftermarket CD player.

OK, that tells us there's a common harness that is spliced into the original wiring. It also tells us that each speaker has its own pin on the harness. An extra task is to inspect the wires from the speaker to the harness, check the pin the wiring goes to, and the connections at the speaker itself. Something could be amiss and is causing this. I suspect that is not the complete problem, though.


No Jumping with the lights. Just happens when the radio on and fans kick in.

I'm interested in seeing what happens after the front frame and HVAC panel grounds are clean.


Not sure about the alternator.. I think it is a replacement.. Could be original or about 6 years old (thats when the last major work was done on the car..)

The reason I point you in that direction is due to the bigger issues you experience. My car has never dies just because a speaker whines and the fans kick on.

The difference in the other car up here was night and day after I cleaned the alternator contacts, the mounting point and tension bracket, and wires. What previously was a struggle is now as you'd expect from a new car. Even if it did not solve the problem, you may notice such side effects as higher voltage at idle, and less voltage drop when the fans come on. It also costs you about a square of sandpaper or one carbon steel dremel brush. The car doesn't even need to be raised!


Are the location of the grounds in the Workshop manual?

No, but there are some lists floating around on here. I do not think there is any one definitive version, but between two or three you can get a complete list that the first one may have overlooked.

Quick list of some of the "big ones" off the top of my head. It is in NO way complete or definitive:
-Negative battery terminal to frame.
-Engine to frame just behind the engine cradle, passenger side
-Front frame crumple section, driver side, where the upper radiator support bolts in.
-HVAC panel, right side. Still requires center console removal.



The low voltage fans are a great idea as well jawn as they draw a lot of power..

I can not say enough good about the fans from DeLorean Parts Northwest. Toby and Misty have a great product there, which is literally plug-and-play, and uses your original shroud should you choose.

[john.frisina]

Yeah the help is fantastic! Thanks!!

Might also be related - my Alternator light sometimes flashes when i go over bumps.. Probably a loose connection somewhere but where to start looking just makes me not want to do it!

The symptoms sound like an earthing problem. When the car has died, it feels like something just drew the power out of it..

Are there any ways of finding out what is the specific location of these points or any pictures of what they look like?? Is all that info buried somewhere in the forum??

[Cory W]

I don't think that's coincidental. It's likely one of the two alternator connections, both of which are easy to access. NOTE: Disconnect your negative battery terminal first.

I took some ground photos once upon a time, but never posted them...let me see how my day progresses. Maybe I'll be able to get to my car and reshoot if I can't find the originals.

Of course, anyone with ground pics may be able to post in the meantime :)

[Rich]

Are there any ways of finding out what is the specific location of these points or any pictures of what they look like?? Is all that info buried somewhere in the forum??
It's in the General Discussion --> Resources folder

22 posts on 3 pages - so far.

http://dmctalk.org/showthread.php?1301

[john.frisina]

It's in the General Discussion --> Resources folder

22 posts on 3 pages - so far.

http://dmctalk.org/showthread.php?1301

Thanks Rich! Gettin' more and more educated.. Now if I only had pics, I'd feel confident on what I'm doing.